The invention relates to improvements in powered airships and more particularly to a powered airship having a flexible envelope inflated and pressurized by hot air and capable of directed flight for transporting loads over distances.
Airships of this type have been referred to as dirigibles and originally referred to as blimps when the airship is nonrigid. The present invention in particular relates to a hot air inflated airship of the nonrigid pressure type. The main envelope or pressure hull is formed of a fabric such as a laminated plastic and Dacron, or of suitable other material which is lightweight, high temperature resistant, extremely strong and impermeable to gas leakage. The envelope of the airship is horizontally elongate and is primarily symmetrical with load lines distributed over the body of the envelope for carrying a payload therebelow. The load lines are also particularly arranged to support hot gas pressure inflation means which preferably will be in the form of one or more propane fueled burners with a fan inflation means. The fan or blower which pressurizes the airship is driven by a suitable motor which may be propane or gasoline fueled. The airship carries a propelling engine and is propeller driven to travel in controlled horizontal flight.
The plastic fabric envelope when not in use can be folded and shipped or stored in the space which takes up less than 1% of its inflated volume. The envelope can be relatively rapidly inflated by the operation of the fan and the free lift is controllable by control of the burner which controls the temperature of the air within the envelope. The direction of flight is controlled by tail fins at the aft end of the airship envelope. These tail surfaces preferably include a rigid or stable portion which stabilizes the airship in horizontal flight, and a manipulable portion which changes the direction of flight. Vertically extending control surfaces are pivoted to the left or right to change the direction of flight, and horizontally extending surfaces move up or down to cause the airship to ascend or descend. Primarily, the temperature of the hot air within the airship is controlled to provide sufficient lift for the weight of the envelope and the payload being carried so that essentially free lift is present while the airship is in flight, and it ascends or descends in accordance with the change in angle of the control tail surfaces.